This invention relates to snowmobiles, and particularly to the power trains thereof. In the past it has been customary to mount the track drive member of the vehicle rigidly in bearings on the vehicle housing, and similarly to mount the various power transmission elements such as the chain case and the drive pulley of the centrifugal clutch rigidly on the housing. The engine in such cases has been resiliently mounted on the housing to in some degree reduce the vibration inherent in such devices and isolate it from the driver. This expedient only partially accomplished its isolation purpose, and added problems of reliability, since with so many mechanical elements mounted on the housing the question of initially obtaining and permanently maintaining a tolerable condition of alignment therebetween becomes very great.